CN104532103B - Method for controlling components of hardenability-ensuring gear steel - Google Patents

Abstract

The invention discloses a method for controlling components of hardenability-ensuring gear steel. The method comprises the following steps of after an LF (Ladle Furnace) enters, supplementing slag materials, rapidly powering, melting the slag materials, carrying out diffusion deoxidation by virtue of a SiO2-Al2O3-CaO slag system, controlling the alkalinity of the slag materials at 3.5-5.5, after a white slag process is performed, sampling at a temperature of above 1560 DEG C, testing, calculating the sum of the contents of Mo, W and 0.2Ni of the test results, determining a control range table applicable in tables 1 to 4, firstly determining the control target value of C in the table and determining the addition of the alloy according to amounts of other elements corresponding to the content of C in the corresponding table and the amounts off other elements of the test results, which is applicable for on-site direct control for the production of a steel 20CrMnTiH. By the calculation, the components meet the requirements of the end hardenability and the target values and deviation values of components are determined. By the production control method, the control target value and the fluctuation range of each element can be specified in one time and the multiple sampling calculations are avoided.

Description

A kind of ingredient control method protecting hardenability pinion steel

Technical field

The invention belongs to metallurgical manufacture field, in particular, provide a kind of ingredient control method protecting hardenability pinion steel.

Background technology

The ability of quench-hardened case (Malpighian layer) depth is obtained when quenching degree represents that steel quenches under certain condition.It is steel A kind of build-in attribute, depends primarily on chemical composition and grain size.And quenching degree is one of key property of pinion steel, pinion steel Requirement to quenching degree also more and more higher.

Protect hardenability pinion steel, in the smelting stage, the qualified premise of quenching degree is to ensure that to the accurate close limit control of composition. Guarantor's hardenability pinion steel of output in domestic and consumption maximum is 20crmntih at present, and the control stress point of this steel grade is by reasonable Alloying component collocation ensureing to obtain narrow hardenability band, particularly under certain c content, the control of mn+cr total amount. In the alloy component range of this steel, c, mn, cr all belong to the element of the quenching degree improving steel；Alloying element ti is added to be to obtain Obtain inherent fine grain steel, can effectively reduce the deformation of steel and cracking etc. in the heat treatment process that coarse grains cause.

The quenching degree computational methods commonly used at present have following several: one is ideal critical diameter method, and it is to be quenched by calculating The ideal critical diameter of permeability, then utilizes water-cooled end hardness and the amplification of ending quenching hardness ratio；Two is just equation, it It is a kind of computing formula that e.just was proposed with nineteen sixty-eight, after numerical transformation has been done to alloying element, using recurrence side Journey calculates acquisition.Both approaches are required to substantial amounts of numerical computations, and not being suitable for production scene needs fast and accurately will Seek the situation of result.

When producing guarantor's hardenability pinion steel, need fast and accurately to chemically examine the composition of steel, calculated according to composition result Component target value, then calculate alloy addition level, then sample examination again, until the scope that composition meets quenching degree requirement is Only.A lot of producers calculate by computer to determine the target component value protecting hardenability pinion steel, although computer has meter at present Calculate the advantages such as speed is fast, numerical value is accurate, but in whole process, need multiple sample examination, and result is inputted computer, weight Multiple labor intensity is very high, and the software for calculating generally requires to develop cooperatively with universities' research institutes, authorizes costly, Improve production cost to a certain extent.

Publication number cn103617354a, the patent of invention of entitled " a kind of the quenching degree of steel general the Fitting Calculation method ", carry Supply a kind of quenching degree general the Fitting Calculation method belonging to iron and steel quenching degree computing technique field, had applied widely, fitted Should be able to power stronger, the feature of prediction of hardenability precision can be effectively improved.But the method needs by means of computer it is adaptable to manage By calculating, it is not suitable for the actual control situation of production scene.

Publication number cn1047697, the patent of invention of entitled " a kind of method producing narrow quenching degree strip steel ", there is provided a kind of Strict strip steel production method is required to H, ending quenching hardness value is forecast using calculating formula, determine or correct the change of steel Learn composition range, to determine grade of steel finally according to end quenching numerical value.The method is to determine grade of steel according to composition and quenching degree numerical value, And can not require to determine Composition Control value range by grade of steel and quenching degree.

Content of the invention

In order to overcome current produced on-site to protect the problem that hardenability pinion steel Composition Control exists, the present invention provides a kind of guarantor The ingredient control method of hardenability pinion steel is it is adaptable to the scene producing 20crmntih steel directly controls.Make composition by calculating Meet the requirement of H, and then determine desired value and the deviation of composition.The control method that it produces can be disposable The control targe value of specified each element and fluctuation range, it is to avoid many sub-samplings calculate.

In order to solve above-mentioned technical problem, the technical solution used in the present invention is: a kind of composition protecting hardenability pinion steel Control method, comprises the following steps:

(1) supplement slag charge after lf enters the station, quickly give electrochemical slag, using sio₂-al₂o₃- cao slag system diffusive deoxidation, slag alkali Degree control in 3.5-5.5, after slag is white, temperature more than 1560 DEG C, sample examination, calculate result of laboratory test mo+w+0.2ni contain Amount, determine in table 1- table 4 be suitable for span of control table:

Table 1 is applied to the alloying element span of control of (mo+w+0.2ni)≤0.01%

Table 2 is applied to the alloying element span of control of 0.01% ＜ (mo+w+0.2ni)≤0.02%

Table 3 is applied to the alloying element span of control of 0.02% ＜ (mo+w+0.2ni)≤0.03%

Table 4 is applied to the alloying element span of control of 0.03% ＜ (mo+w+0.2ni)≤0.04%

In above-mentioned table, data is mass percent, unit %；

(2) the corresponding form being determined according to mo+w+0.2ni content in step (1), determines the control of a c in table first Desired value processed, then the amount according to remaining element of this c content remaining amount of element corresponding and result of laboratory test in corresponding table is Lai really Determine the addition of alloy, alloy addition computational methods are:

Ton steel alloy addition is multiplied by molten steel amount as alloy answers addition.

The invention has the beneficial effects as follows: it is applied to the scene directly control producing 20crmntih steel.Make composition by calculating Meet the requirement of H, and then determine desired value and the deviation of composition.The control method that it produces can be disposable The control targe value of specified each element and fluctuation range, it is to avoid many sub-samplings calculate.

Specific embodiment

With reference to specific embodiment, the present invention is described in further detail:

The preparation method of guarantor's hardenability pinion steel of the present invention is identical with prior art, may be referred to prior art, So no longer describing, the present invention and the difference of prior art be protect hardenability pinion steel ingredient control method different, below It is described in detail:

Because c element affects maximum to quenching degree, and the scope control precision highest to c element in producing, first really The span of control determining c is 0.18-0.22%, with 0.01% as step-length, calculates the control targe determining mn, cr, si respectively, and then Determine each allowable fluctuation range affecting quenching degree element in addition to c.

In 20crmntih steel, the content of the residual elements such as mo, w, ni can affect quenching degree to a certain extent, so needing root According to its actual content range, determine other alloying element span of control values of corresponding scope.In order to simplify in actual production Control, the control targe value of mn, cr element disposably specified and deviation, such as table 1- table 4, in table, data is percent mass Than.

Table 1 is applied to the alloying element span of control of (mo+w+0.2ni)≤0.01%

Table 2 is applied to the alloying element span of control of 0.01% ＜ (mo+w+0.2ni)≤0.02%

Table 3 is applied to the alloying element span of control of 0.02% ＜ (mo+w+0.2ni)≤0.03%

Table 4 is applied to the alloying element span of control of 0.03% ＜ (mo+w+0.2ni)≤0.04%

In above-mentioned table, data is mass percent, unit %；

Specific control method is as follows:

Lf supplements slag charge after entering the station, quickly give electrochemical slag, using sio₂-al₂o₃- cao slag system diffusive deoxidation, basicity of slag Control in 3.5-5.5.After slag is white, temperature more than 1560 DEG C, sample examination.Calculate the mo+w+0.2ni content of result of laboratory test, Determine the span of control table being suitable in table 1- table 4.Determine the control targe value of a c first in table, then according in this table The addition to determine alloy for the amount of remaining element of this c content remaining amount of element corresponding and result of laboratory test.Alloy addition Computational methods are:

Ton steel alloy addition is multiplied by molten steel amount as alloy answers addition.

Embodiment 1:

Lf carries out deoxidation and reduction, and rear sample examination composition is (unit %) to slag in vain:

c	si	mn	p	s	cr	ti	mo	w	ni
										0.11	0.12	0.84	0.010	0.005	1.01	0	0	0	0.10

Mo+w+0.2ni=0.02, meets 0.01% ＜ (mo+w+0.2ni)≤0.02% scope, therefore according to the mesh of table 2 Scale value and fluctuation range are come with addition of alloy.The alloy adding is needed to be: ferrosilicon, ferromanganese, ferrochrome, ferrotianium are it is known that the product of each alloy Position is: ferrosilicon contains si75%, and ferromanganese contains mn78%, and ferrochrome contains cr65%, and ferrotianium contains ti 30%.Each alloy recovery is: ferrosilicon 88%, ferromanganese 94%, ferrochrome 94%, ferrotianium 50%.Choose c=0.20% mono- behavior desired value, that is, si desired value is 0.22%, Mn desired value is 0.93%, cr desired value is 0.07% for 1.16%, ti desired value, calculates ton steel alloy addition and is respectively as follows:

Read molten steel weighing amount and be 106 tons, calculate each alloy answers addition (kg):

Ferrosilicon	Ferromanganese	Ferrochrome	Ferrotianium
				161	130	260	495

After adding above-mentioned alloy, sample examination composition, adds carbon dust according to c content now, c content is adjusted by carbon iron ball Whole is 0.20%.

The ultimate constituent is (unit %):

c	si	mn	p	s	cr	ti	mo	w	ni
										0.20	0.23	0.92	0.011	0.005	1.15	0.053	0	0	0.10

Embodiment 2:

Lf carries out deoxidation and reduction, and rear sample examination composition is (unit %) to slag in vain:

c	si	mn	p	s	cr	ti	mo	w	ni
										0.09	0.16	0.86	0.014	0.006	1.01	0	0	0	0.10

Mo+w+0.2ni=0.02, meets 0.01% ＜ (mo+w+0.2ni)≤0.02% scope, therefore according to the mesh of table 2 Scale value and fluctuation range are come with addition of alloy.The alloy that needs add is: ferrosilicon, ferromanganese, ferrochrome, ferrotianium, alloy grade and recovery Rate is with embodiment 1.Choose c=0.20% mono- behavior desired value, that is, si desired value is 0.93%, cr for 0.22%, mn desired value Desired value is 1.16%, ti desired value is 0.07%, calculates ton steel alloy addition and is respectively as follows:

Read molten steel weighing amount and be 102 tons, calculate each alloy answers addition (kg):

Ferrosilicon	Ferromanganese	Ferrochrome	Ferrotianium
				93	97	250	476

After adding above-mentioned alloy, sample examination composition, adds carbon dust according to c content now, c content is adjusted by carbon iron ball Whole is 0.20%.

The ultimate constituent is (unit %):

c

si

mn

p

s

cr

ti

mo

w

ni

0.20

0.24

0.92

0.015

0.005

1.14

0.078

0

0

0.10

Embodiment 3:

Lf carries out deoxidation and reduction, and rear sample examination composition is (unit %) to slag in vain:

c	si	mn	p	s	cr	ti	mo	w	ni
										0.11	0.13	0.78	0.015	0.006	1.01	0	0	0	0.11

Mo+w+0.2ni=0.022, meets the scope of 0.02% ＜ (mo+w+0.2ni)≤0.03%, therefore according to table 3 Desired value and fluctuation range come with addition of alloy.Need add alloy be: ferrosilicon, ferromanganese, ferrochrome, ferrotianium, alloy grade and The response rate is with embodiment 1.Choose c=0.20% mono- behavior desired value, that is, si desired value for 0.22%, mn desired value is 0.92%, cr desired value is 1.16%, ti desired value is 0.07%, calculates ton steel alloy addition and is respectively as follows:

Read molten steel weighing amount and be 105 tons, calculate each alloy answers addition (kg):

Ferrosilicon	Ferromanganese	Ferrochrome	Ferrotianium
				143	200	258	490

After adding above-mentioned alloy, sample examination composition, adds carbon dust according to c content now, c content is adjusted by carbon iron ball Whole is 0.20%.

The ultimate constituent is (unit %):

c	si	mn	p	s	cr	ti	mo	w	ni
										0.20	0.24	0.93	0.013	0.005	1.14	0.088	0	0	0.11

Embodiment 4:

Lf carries out deoxidation and reduction, and rear sample examination composition is (unit %) to slag in vain:

c	si	mn	p	s	cr	ti	mo	w	ni
										0.13	0.13	0.84	0.011	0.006	1.01	0	0	0	0.10

Mo+w+0.2ni=0.02, meets 0.01% ＜ (mo+w+0.2ni)≤0.02% scope, therefore according to the mesh of table 2 Scale value and fluctuation range are come with addition of alloy.The alloy that needs add is: ferrosilicon, ferromanganese, ferrochrome, ferrotianium, alloy grade and recovery Rate is with embodiment 1.Choose c=0.20% mono- behavior desired value, that is, si desired value is 0.93%, cr for 0.22%, mn desired value Desired value is 1.16%, ti desired value is 0.07%, calculates ton steel alloy addition and is respectively as follows:

Read molten steel weighing amount and be 101 tons, calculate each alloy answers addition (kg):

Ferrosilicon	Ferromanganese	Ferrochrome	Ferrotianium
				138	124	248	471

After adding above-mentioned alloy, sample examination composition, adds carbon dust according to c content now, c content is adjusted by carbon iron ball Whole is 0.20%.

The ultimate constituent is (unit %):

c	si	mn	p	s	cr	ti	mo	w	ni
										0.20	0.24	0.92	0.010	0.006	1.16	0.090	0	0	0.10

The quenching degree testing result of table 5 embodiment

	j9	j15
			Example 1	38.8	32.7

Example 2	38.3	32.1
			Example 3	39.4	31.5
Example 4	38.7	32.1

Table 5 is the testing result of quenching degree.It can be seen that the quenching degree fluctuation range of final finished is narrower, thus ensure that gear The steady quality of product made from steel.

Embodiment described above is merely to illustrate technological thought and the feature of the present invention, its object is to make in the art Technical staff it will be appreciated that present disclosure and according to this implement it is impossible to only to limit the patent model of the present invention with the present embodiment Enclose, equal change or modification that is, all disclosed spirit is made, still fall in the scope of the claims of the present invention.

Claims (1)

1. a kind of ingredient control method protecting hardenability pinion steel is it is characterised in that comprise the following steps:

(1) supplement slag charge after lf enters the station, quickly give electrochemical slag, using sio₂-al₂o₃- cao slag system diffusive deoxidation, basicity of slag control System in 3.5-5.5, after slag is white, temperature more than 1560 DEG C, sample examination, calculate result of laboratory test mo+w+0.2ni content, really Determine in table 1- table 4 be suitable for span of control table:

Table 1 is applied to the alloying element span of control of (mo+w+0.2ni)≤0.01%

Table 2 is applied to the alloying element span of control of 0.01% ＜ (mo+w+0.2ni)≤0.02%

Table 3 is applied to the alloying element span of control of 0.02% ＜ (mo+w+0.2ni)≤0.03%

Table 4 is applied to the alloying element span of control of 0.03% ＜ (mo+w+0.2ni)≤0.04%

In above-mentioned table, data is mass percent, unit %；

(2) the corresponding form being determined according to mo+w+0.2ni content in step (1), determines the control mesh of a c in table first Scale value, then determines conjunction according to the amount of remaining element of this c content remaining amount of element corresponding and result of laboratory test in corresponding table The addition of gold, alloy addition computational methods are:

Ton steel alloy addition is multiplied by molten steel amount as alloy answers addition.